Electric plug and socket



May 21, 1935. H. P. HASTINGS 2,002,177

ELECTRIC PLUG AND SOCKET Filed June '7, 1930 2 Sheets-Sheet l A TTORNEY$.

May 21, 1935. H. P. HASTINGS 2,002,177

ELECTRIC PLUG AND SOCKET Filed June 7, 1950 2 Sheets-Sheet 2 ATTORNEYS.

- Patented May 21,1935

' UNITED STATES PATENT omen e Claims. (01. 113F328) This invention relates to electrical plugs and sockets, andhas for its object, a particularly simple and eillcient means for primarily preventing complete withdrawal of the plug from the socket after the plug terminals and socket members are separated, but before the plug is entirely withdrawn from the socket, so as to prevent the ignition of explosive gases in the locality of the plug and socket member by arcing between the plug and socket terminals while they are being separated.

The invention consists in the novel features and in the combinations and constructions hereinafter set "forth and claimed.

iii In describihg this invention, reference is had to the accompanying drawings in which like Figure 2 is a fragmentary view, the casings of the plug and socket member being shown in section, and the insulation which supports the terminals being shown in elevation, .the guide mem- 80 ber being shifted into its positionoccupied for permitting a complete withdrawal of the plug. Figure 3 is an elevation, partly broken away,

showing the plug member as completely withdrawn from the socket member.

86 Figure 4 is an end view of the plug member. Figure 5 is an end 'view of the socket member. Figure 6 is 'an end view of the plug member looking to the left, Figured, showing the guide member in its position assumed after the plug 40 has been withdrawn far enough to separate the plug and socket terminals, but before the plug terminals have left the are tight passages of the socket member.

Figure 7 is a view similar to Figure 6 showing 45 the guide member as shifted about its Figure 8 isa developed view of the interior of the guide member.

The preferred embodiment of my invention comprises generally a ,socket member having 50 terminals therein, and a plug member movable into and out of the socket member and having terminals for cooperating with the former terminals, a third member usually carried by the 7 socket member and formed with a zigzag guide, 7 or a guide having substantially straight portions extending lengthwise thereof arranged out e:-

alinement or staggered, and an angular or transverse portion or passage connecting the straight portions. the plug member having guidemeans as shoulders movable along the guide of the 8 third member, the third member having a rotary movement for bringing the straight portions bf the guide into alinement with the shoulder on the plug, the straight portions and the angular portions being so located that the plug is stopped, 10 7 of the invention herein "described, this means con- 30 sists of a bayonet joint interlock between the plug-and a. rotating sleeve on the socket.

An important feature of this invention. is to provide a circuit breaking plug and receptacle whereby there must be a momentary delay betemperature of any flammable mixture of air and dust'or gases that may be in the vicinity of the plug and the socket. i The socket member comprises a suitable tubular casing I, and an internal block 2 of insulation in which are mounted terminals 3, these being located in are tight passages 4 formed in the block of insulation 2. Thecasing is mounted on a suitable, support 5 through which the service. wires 6 enter, these being secured in any suitable manner to the terminals 3. 40

The plug member likewise comprises a tubular casing I having a support of insulation 8 in which are mounted terminals 9 for coacting with the terminals 3, the advance ends of the terminals 9 entering the passages l. 46

In the illustrated embodiment of the invention, the terminals 9 are formed with sockets II at their ends which receive the ends of the terminals 3. The plug member I is provided with a A suitable end or stem ll through which the wires 50 I! enter, these being connected to the terminals 9 in any suitable manner.

The construction thus far described, per se, forms no part of this invention.

The means for preventing complete separation 56 the plug and socket members, and an interme-' diate angular or transverse portion, the plug member having. means as shoulders movable along-the guide, the guide member capable of rotative movement to bringone or the other of the lengthwise portions into alinement with the shoulders when the plug member is part way in,

' or part way out of the socket in order that the plug member maybe operated to complete its movement.

l3 designates the guide member which is rotatably mounted on the casing I of the socket member, it being shown as screw threaded thereon,

and when once placed inposition, heldfrom unedue rotative movement'by a stop pin I4 extendinginto the casing of the socket member I and having its outer end located in a slot or notch l5 formed in the rear end of the guide member l3. the pin limiting the rotative movement of the 1 guide member.

its

In the illustrated embodiment of my invention, the guide'member is formed with internal lengthwise projections' or guides l6 extending from near its end and terminating short of the outer end in a stop shoulder l6 and with end projections I! at its outer end out of alinement or staggered with respect to the projections l6 and formed with a transverse passage l8 at the outer end of the projections l6; and the plug is formed with diametrically extending shoulders I!) with spaces 20 between their ends complemental to the projections II. There are a plurality, preferably two projections l8 located diametrically opposite each other and twoprojections i'l similarly located. 'The inner faces l'l of the projections l1 and the outer ends l8 of the projection l6 constitute shoulders located in planes spaced apart and forming the transverse passage l8.

In order that the plug can! be inserted in the socket only in one position so that proper pairs of terminals '3 and ID will coact,,the socket is provided withan internal shoulder II and the plug with a lengthwise groove 22. ,I'he shoulder and the lengthwise groove also prevent relative tuming or tendency to turn of the plug and socket during withdrawal of the plug and during turning of the guide member.

r In operation, the guide member l3 must be in the position shown in Figure? in which the projections i1 permit the plug shoulders l9 to be inserted into the guide member it between the outer projection l1 and against the end faces I6 '01 the projection l6 and in line with the transverse passage ll. r After the plug has been partially inserted in the socket with the shoulders I! against the ends of the projections IS, the guide member I! is given a partial turn to move the projections 16 out of alinement with the shoulders l9, Figure 6, and the spaces 20 in alinement with said projections It so that the plug can -be completely inserted to bring the pairs of terminals 8, 10 into' contact, this turning of the guide member l3 bringing the projections l'l into interlocking engagement with the shoulders l9 to prevent uninterrupted withdrawal of the plug from the socket. To withdraw the plug from the socket, the plug is-ilrst pulled outwardly until the shoulders it come against the faces ll of the projections l1 and into alinement with the transverse passages l8, and then to complete the withdrawal of the plug, the guide member I! is turned to move the projections into alinement with the spaces 20. If an attempt is made to' insert the plug into the socket by first turning the guide member, the shoulder I! will encounter the outer sides ofthe projections II and hence, the guide member must be turned to-proper position to permit the plug to be inserted until the shoulders I! come against the ends of the projections It.

,In order that the plug and socket may be arc tight when the plug is but partially withdrawn, the passages 4 of the insulation 2 of the socket and the terminals II are long enough so that theends' of the terminals II are in the are tight passages when the plug is partly withdrawn with the shoulders l9 obstructed by the end projections ll. Hence, it is necessaryto have the guide member lrotatable instead of the plug member o; the socket member". Although the guide mem terminals 3 but both are locatedin the are tight passages. 4.

What I claim is:

1. In an electric piugand socket, the combination of a socket member having terminals therein, and a plug member movable into and out of the socket and having terminals for coacting with.the former terminals, a stop member for preventing the withdrawal of the plug member from the socket member when the terminals are" separated, and before the plug and socket members are separated, the stop member being movable about its axis for releasing the'plug member from the stop member to permit complete withdrawal of the plug member, and means for preventing turning of the plug member relative to the socket member during the insertion and withdrawal of the plug member and during the turning of the stop member.

2. In an electric plug and socket, the combination of a socket member having terminals therein, and are tight passages around the terminals, a plug member movable into and out of the socket and having terminals for entering said passages and cooperating with the former terminals, a 1? third member carried by the socket member and formed with a guide foxthe plug member, said guide having an intermediate angular portion, and the plug member being provided with means movable along the guide, the angular portion of the guide forming a stop for stopping the withdrawingmovement of the plug member after the terminals thereof are separated from the terminals of the socket member, and before the plug terminals have left the are tight passages and the plug and socket members arecompletely separated, the third member having a partial rotative movement for moving the angular portion of the,guide out of en agement with the means on the plug member, whereby the plug can he completely withdrawn. 3. In an electric. plug and socket, the combina tion of a socket member having terminals therein, and are tight passages around the terminals,

ist

a plug member movable into and out of the socket 5 -nals of the socket member and before the plug terminals have left the are tight passages and the plug and socket members are completely separated, the third member having a partial rotative movement for moving the angular portion of the guide out of engagement with the means on the plug member, whereby the plug can be completely withdrawn, the plug and socket members having coacting key and groove means for preventing the entrance of the plug into the socket except in a predetermined position.

4. In an electric plug and socket comprising a socket member having terminals therein and are tight passages around the terminals, the plug member being movable into and out, of thesocket, and having terminals for entering the passages and coacting with the former terminals, a third member carried by the socket member and being formed with internal projections arranged out of lengthwise alinement and with a space between the planes of their opposing ends, and the opposing ends of the projections forming stops for preventing endwise movement of the plug, and the plug member having a projection movable along the lengthwise projections and transversely through said space out of alinement with one projection into alinement with-the other, the third member having a-rotative movement for moving the projections of the third member relatively to the projection of the plug member when the plug member is alined with said space to bring one of the projections of the third mem-' ber out of alinement with the projection of the plug and the other projection of the third member into alinement with the projection of the plug member.

5. In an electric plug and socket comprising a socket member having terminals. therein and are tight passages around the terminals, the plug member being movable into and out of the socket,

and having terminals for entering the passages and coacting with the former terminals, a third member carried by the socket member and being formed with internal projections arranged out of lengthwise, alinement and with a space between the planes of their opposing ends, and the opposing ends of the projections forming stops for preventing endwise movement of the plug, and the plug member having a projection movable along the guide, the third member having a rota,- tive movement for moving the projections of the third member relatively to the projection of the plug member when the plug member is alined with saidspace ,to bring one of the projections of the third member out of alinement withthe projection of the plug and the other projection of the third member into alinement with the projection of the plug member, the plug and socket member having coacting means for guiding the plug member in a predetermined position into the socket member.

6. In an electric plug and socket, the combination of a socket member having terminals therein and are tight passages around the terminals, a

plug member movable into and out of the socket guide having an intermediate angular portion,

and the plug member being provided with means movable along the guide, the angular portion of the guide forming a stop for preventing the withdrawing movement of the plug member after the terminals thereof are separated from the terminals of the socket member, and before the plug terminals have left the are tight passages the plug and socket member is completely separated from the socket member, the third member being rotatably mounted on the socket member for bringing the angular portion of the guide out of alinement with the guide means on the plug member. I

7. An electric plug and socket comprising a socket member having terminals therein and are tight passages around the terminals, and the plug member movable into and out of the socket,

and having terminals for entering the passages the plug member is being withdrawn out of the socket member. Y 8. In an electric plug and socket, the combination of a socket member having terminals therein and a plug member movable axially rectilinearly out of the socket member, and means for stopping the axial withdrawing movement of the plug member after the terminals are separated and before the plug and socket members are separated, said means being movable about the axis of the plug and socket members to permit complete withdrawal of the plug member, and means connecting the plug and socket members to aline the terminals thereof and relieve them of strains tending to misaline them during the turning of said means.

9. In an electric plug and socket, the combination of a socket member having terminals there'- in, a plug member having terminalsfor coacting with the former terminals, the plug member being movable rectilinearly into and out of the socket, a stop member carried by the socket member substantially concentric therewith and co-' acting with the plug member to stop the withdrawing movement of the plug member after ,the terminals are completely separated and before member during the turning of the stop member.

HAROLD P. nas'rmas. 

